Digital broadcasting receiver

BACKGROUND OF THE INVENTION

0001The present invention relates to a digital broadcasting receiver that uses broadcast channel map information containing channel numbers and virtual channel numbers.

0002Conventionally, there have been televisions equipped with broadcast channel memories, memories for identifying broadcast stations, etc., which read broadcasting station identification codes for the channels being received, and automatically rewrite desired channels to be received to new broadcast channels by going through search processes when the broadcast channels are changed (e.g., Japanese Unexamined Patent Publication No.11-18018).

0003Furthermore, in recent years, broadcasting stations in North America have been distributing digital broadcasts based on the ATSC (Advanced Television Systems Committee) Standards. As a result, certain types of broadcasting receivers (set top box; hereinafter called “STB”) are becoming popular that receive these digital broadcasts and convert them into image signals that can be received by existing televisions. The STB typically is equipped with table data (“channel map”), which stores in an internal memory the data included in the broadcasting signal at the time when the broadcasting signal is received, and this channel map is used for the purpose of station selection later. It is possible to provide the STB with a capability of automatically rewriting the desired channel to be received to a new broadcast channel by going through the abovementioned search process.

0004However, the STB of the prior art could not select a station if the digital channel number inputted by a user was not registered in the channel map, so that it used to notify the user that there was no signal even though the broadcasting signal actually existed. More specifically, it was designed in such a way that a digital broadcasting signal could contain information data such as multiple channels (sub-channels) and virtual channel numbers in the same frequency band (“physical channel”), but it was not possible to select stations if the user knew only virtual channel numbers.

SUMMARY OF THE INVENTION

0005It is an object of the present invention to solve the abovementioned problems and to provide a digital broadcasting receiver that is capable of, even when the information concerning an arbitrary digital channel number inputted by the user has not been registered in the channel map and therefore the particular broadcast cannot be selected, scanning the broadcasting signal band and selecting the digital broadcasting signal that has the number as the virtual channel in compliance with the instruction by the user thereafter.

0006In the present invention, a digital broadcasting receiver comprises: an input unit for entering station selection and other instructions into the receiver; a receiving unit for receiving coded digital/analog broadcasting signals transmitted by a broadcasting station in accordance with the station selection instructions; a digital/analog decoding unit for decoding the digital/analog broadcasting signals received by the receiving unit, and outputting the decoded signals to a display device connected to the receiver for displaying images; a memory for storing broadcast information as a channel map to be used during station selection; and a control unit for controlling the units including the input and output units, and the memory, wherein the control unit executes: a process of searching a digital channel number in the channel map stored in the memory when the number is entered from the input unit, and as a result, receiving a broadcast corresponding to the number when the number is found, and notifying that no signal exists when the number is not found; and a process of scanning frequency band of the broadcasting signal by the receiving unit and the decoding unit when the number is not found as a result of the search and a scan instruction is entered by a user, and as a result, receiving a broadcast corresponding to the digital channel number when a signal for the number is found, and notifying that no such a signal exists when it is not found.

0007In this configuration, when the user enters the digital channel number, the control unit makes the search to see whether there is a corresponding number in the channel map stored in the memory, and receives the corresponding broadcast if the number exists, or notifies the user that no signal exists if the number does not exist. When the number does not exist in the channel map and the user enters the scan instruction, the control unit scans the broadcasting signal frequency band and, as a result, receives the broadcast if the signal of the digital channel number exists, or notifies the user that there is no signal if no signal exists. Thus, it is possible to search the digital channel number inputted arbitrarily by the user.

0008In the digital broadcasting receiver of the present invention, the control unit may further execute a process of switching the scanning function between enabling and disabling.

0009In this configuration, it is possible to avoid the scanning for selecting stations when the user does not intend to scan.

0010In the present invention, a digital broadcasting receiver comprises: an input unit for entering station selection and other instructions into the receiver; a receiving unit for receiving coded digital/analog broadcasting signals transmitted by a broadcasting station in accordance with the station selection instructions; a digital/analog decoding unit for decoding the digital/analog broadcasting signals received by the receiving unit, and outputting the decoded signals to a display device connected to the receiver for displaying images; a memory for storing broadcast information as a channel map including channel numbers and virtual channel numbers to be used during station selection; an OSD output unit for displaying specified on-screen display (“OSD”) on the display device, and a control unit for controlling the units including the input and output units and the memory, wherein the control unit executes: a process of searching a digital channel number in the channel map stored in the memory when the number is entered from the input unit; a process of receiving a broadcast corresponding to the number when the number is found as a result of the search, and outputting a signal for OSD-displaying on the display device a notice that no signal exists when the number is not found; a process of scanning the entire range of frequency band of the broadcasting signal by the receiving unit and the decoding unit when the number is not found as a result of the search and a scan instruction is entered by a user; a process of receiving a broadcast corresponding to the digital channel number when a signal for the number is found as a result of the scan, and notifying that no such a signal exists when it is not found; and a process of switching the scanning function between enabling and disabling.

0011In this configuration, when the user enters a digital channel number (e.g., <b>12</b>-<b>2</b>), the control unit searches if the number exists in the channel map stored in the memory, and receives the corresponding broadcast if the number exists, or OSD-displays on the display device no-signal message (e.g., “no signal”) if the number does not exist. If the user enters the scan instruction when the number does not exist, the control unit scans the entire range of frequency band of the broadcasting signal, and receives the broadcast if the signal of the digital channel number exists, and notifies the user that no signal exists if no such signal exists. Thus, even when the user knows only the virtual channel number, it can be searched. Also, the abovementioned scanning function normally requires some time to scan multiple broadcasting channels from the start to the end, however, it is possible to avoid selecting stations when the user does not intend to select by switching between enabling and disabling of the scanning function.

BRIEF DESCRIPTION OF THE DRAWINGS

0012<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram of a digital broadcasting receiver according to an embodiment of the present invention.

0013<figref idref="DRAWINGS">FIG. 2</figref> is a block diagram of the TS (Transport Stream) analysis circuit of the receiver.

0014<figref idref="DRAWINGS">FIG. 3</figref> is a flowchart of the operation process by the control unit of the receiver.

0015<figref idref="DRAWINGS">FIG. 4</figref> is a diagram showing a channel map stored in the memory of the receiver.

0016<figref idref="DRAWINGS">FIG. 5</figref> is a view of the television display when the receiver is receiving a digital channel input.

0017<figref idref="DRAWINGS">FIG. 6</figref> is a view of the television display when the receiver is tuned to a virtual channel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE PRESENT INVENTION

0018A digital broadcasting receiver (set top box; “STB”) according to an embodiment of the present invention will be described below referring to the accompanying drawings. <figref idref="DRAWINGS">FIG. 1</figref> is a block diagram of an STB. A STB <b>1</b> is a device for receiving by an antenna <b>10</b> a digital broadcasting signal encoded according to ATSC and broadcasted from a television station in accordance with the user's operation input by using an input unit <b>11</b> such as push buttons or a remote control unit, and thus converting it to an image signal based on NTSC to be displayed on a display device <b>12</b>.

0019The STB <b>1</b> comprises a tuner <b>2</b> (receiving unit) for receiving the digital broadcasting signals transmitted according to the modulation format of 8VSB (Vestigial Side Band), a TS conversion circuit <b>4</b> for converting the digital broadcasting signals received by the tuner <b>2</b> into transport streams (hereinafter called “TS”), a TS analysis circuit <b>6</b> for decoding image signals by analyzing the TS signals converted by the TS conversion circuit <b>4</b> and displaying images on the display device <b>12</b>, a memory <b>7</b> for storing a channel map information of a transmission frequency, a channel number and a virtual channel number etc. of each main channel of the digital broadcast, an audio output circuit <b>9</b> for extracting the digital audio signal of a specific broadcasting language and causing a speaker <b>15</b> to generate audio outputs, and a control unit <b>8</b> consisting of a CPU for controlling each unit of the receiver. The channel map information is registered by scanning the entire range of frequency band of the broadcasting signal during the initialization of the receiver and is used for selecting stations later.

0020The tuner <b>2</b> receives digital broadcasting signals received by the antenna <b>10</b>, selects a station in accordance with an instruction entered by the user into the control unit <b>8</b> using the input unit <b>11</b>, and receives 8VSB-modulated digital broadcasting signals existing in the frequency range corresponding to the channel inputted by the user. The TS conversion circuit <b>4</b> converts the 8VSB-modulated broadcasting signals received by the tuner <b>2</b> into the TS signals.

0021The TS analysis circuit <b>6</b> analyzes the TS signals converted by the TS conversion circuit <b>4</b>, and outputs image signals added with OSD displays as needed to the display device <b>12</b>. <figref idref="DRAWINGS">FIG. 2</figref> is a block diagram of the TS analysis circuit <b>6</b>. The TS analysis circuit <b>6</b> comprises a transport parser <b>6</b><i>a </i>(signal extraction unit), an external memory interface <b>6</b><i>b</i>, a video decoder <b>6</b><i>c </i>(digital decoding unit), a display controller <b>6</b><i>d</i>, an OSD circuit <b>6</b><i>e </i>(OSD output unit), a digital video encoder <b>6</b><i>f</i>, an audio interface <b>6</b><i>g</i>, a host processor interface <b>6</b><i>h</i>, and a PLL (Phase Locked Loop) circuit <b>6</b><i>i</i>. The transport parser <b>6</b><i>a </i>acquires TS signals transmitted from the TS conversion circuit <b>4</b>, and parses them to image signals, audio signals and control signals. The external memory interface <b>6</b><i>b </i>receives instruction from the control unit <b>8</b> via the host processor interface <b>6</b><i>h</i>, and controls connections with the transport parser <b>6</b><i>a</i>, the video decoder <b>6</b><i>c</i>, and the display controller <b>6</b><i>d </i>as well as with the memory <b>7</b>. For example, image signals, audio signals, and control signals parsed by the transport parser <b>6</b><i>a </i>are stored into the memory <b>7</b> via the external memory interface <b>6</b><i>b </i>respectively.

0022Upon receiving an instruction from the control unit <b>8</b>, the video decoder <b>6</b><i>c </i>retrieves the image signals stored in the memory <b>7</b> to be decoded. Upon receiving an instruction from the control unit <b>8</b>, the display controller <b>6</b><i>d </i>converts the image signals decoded by the video decoder <b>6</b><i>c </i>into the NTSC format. Upon receiving an instruction from the control unit <b>8</b>, the OSD circuit <b>6</b><i>e </i>sends out the image signals converted into the NTSC format by the video decoder <b>6</b><i>c </i>to the digital video encoder <b>6</b><i>f</i>, and also sends out image signals attached with an OSD display as needed to the digital video encoder <b>6</b><i>f</i>. Upon receiving an instruction from the control unit <b>8</b>, the OSD circuit <b>6</b><i>e </i>executes an arithmetic processing to add an OSD display for each frame of an image signal in order to make OSD display in specified colors on the display device <b>12</b>. The OSD circuit <b>6</b><i>e </i>also has a built-in memory for executing the abovementioned arithmetic processing.

0023Upon receiving an instruction from the control unit <b>8</b>, the digital video encoder <b>6</b><i>f </i>converts image signals received from the OSD circuit <b>6</b><i>e </i>into analog signals to be outputted to the display device <b>12</b>. The audio interface <b>6</b><i>g </i>sends out audio signals parsed by the transport parser <b>6</b><i>a </i>to the audio output circuit <b>9</b>. The host processor interface <b>6</b><i>h </i>transmits instructions from the control unit <b>8</b> to the transport parser <b>6</b><i>a</i>, the external memory interface <b>6</b><i>b</i>, the video decoder <b>6</b><i>c</i>, the display controller <b>6</b><i>d</i>, the OSD circuit <b>6</b><i>e</i>, and the digital video encoder <b>6</b><i>f</i>. The PLL circuit <b>6</b><i>i </i>causes a local oscillation frequency to match with a specified frequency based on an inputted clock signal.

0024The memory <b>7</b> stores channel information concerning transmission frequency, etc., of each channel, and menu items, etc., concerning the receiver setup. The memory <b>7</b> also stores control signals parsed by the transport parser <b>6</b><i>a</i>. The control unit <b>8</b> controls each unit through a data-bus upon receiving the user's instructions entered by means of the input unit <b>11</b>. For example, the control unit <b>8</b> analyzes a VCT (Virtual Channel Table) by retrieving the control signals which have been parsed by the transport parser <b>6</b><i>a </i>and stored in the memory <b>7</b>, acquires the channel information of the channel currently being received based on status signals included therein, and outputs this channel information on the display device <b>12</b> via the OSD circuit <b>6</b><i>e </i>and the digital video encoder <b>6</b><i>f. </i>

0025The audio output circuit <b>9</b> converts audio signals acquired from the audio interface <b>6</b><i>g </i>to audio signals for the speaker <b>15</b>, to output the audio signals to the speaker <b>15</b>. More specifically, it extracts audio signals according to an instruction by the control unit <b>8</b>, and decodes them to convert into analog signals. The input unit <b>11</b> is a device used for inputting the user's instructions such as channel switching to the control unit <b>8</b>. Examples of the input unit <b>11</b> include push buttons provided on the front of the STB <b>1</b> and a remote control unit used for giving operation instructions for the STB <b>1</b> by means of infrared rays. The display device <b>12</b> can be a display of a television, a CRT, a flat panel display device such as an LCD (Liquid Crystal Display) and a PDP (Plasma Display Panel). If the display device <b>12</b> is capable of accepting digital signal input, the system can be configured by directly connecting the OSD circuit <b>6</b><i>e </i>with the input terminal of the display device <b>12</b> without going through the digital video encoder <b>6</b><i>f</i>. The speaker <b>15</b> is connected to the audio output circuit <b>9</b>, and generates audio output based on audio signals processed by the audio output circuit <b>9</b>.

0026The control unit <b>8</b> in this embodiment executes: a process of searching whether or not a digital channel number exists in the channel map stored in the memory <b>7</b> when the digital channel number is entered by the user via the input unit <b>11</b>; a process of receiving the corresponding broadcast if the number is found as a result of the search, or outputting a signal for OSD-displaying the no-signal message if the number is not found; a process of scanning the entire range of frequency band of the broadcasting signal when a scan instruction is entered by the user via the input unit <b>11</b> as the number is not found as a result of the search; a process of receiving the corresponding broadcast if the signal of the digital channel number is found as a result of the scan, or outputting a signal for OSD-displaying the no-signal message if the signal is not found; and a process of switching between enabling and disabling the scanning function according to the user's instruction input.

0027<figref idref="DRAWINGS">FIG. 3</figref> is the operation process of the control unit <b>8</b> when receiving a digital channel input by the user. When the user enters a digital channel number (e.g., <b>12</b>-<b>2</b>) via the input unit <b>11</b>, the control unit <b>8</b> searches whether or not the number exists in the channel map of the memory <b>7</b> (#<b>1</b>), and receives the broadcast if the number exists (#<b>1</b>: Yes), or OSD-displays on the display device <b>12</b> no-signal message (e.g., “no signal”) if the number does not exist (#<b>1</b>: No, #<b>2</b>). If the user enters another operation instruction for station selection when no corresponding number exists (#<b>3</b>: Yes), the control unit <b>8</b> returns to #<b>1</b>. If the user does not enter another operation instruction for station selection (#<b>3</b>: No) and enters a scan instruction (Enter key, Search key, etc., on the input unit <b>11</b>) as an additional input (#<b>4</b>: Yes), the control unit <b>8</b> scans the entire range of frequency band of the broadcasting signal (#<b>5</b>), and if the signal for the digital channel number exists as a result (#<b>6</b>: Yes), the control unit <b>8</b> receives the broadcast (#<b>7</b>), or, if the signal does not exist (#<b>6</b>: No), OSD-displays the result (detection failure) (#<b>8</b>).

0028Thus, even in a case when the user knows only the virtual channel number and no-signal results because the virtual channel number information is not registered in the channel map, the virtual channel can be searched by means of additional input of a scan instruction. Also, since enabling/disabling of the scanning function can be switched, it is possible to avoid the scanning for selecting stations when the user does not want to scan by disabling the function.

0029Next, a specific case is described referring to <figref idref="DRAWINGS">FIG. 4</figref> through <figref idref="DRAWINGS">FIG. 6</figref>. <figref idref="DRAWINGS">FIG. 4</figref> is an example of a channel map stored in the memory <b>7</b>. It is assumed that a physical channel (CH NUMBER) 10 ch is a digital channel having a virtual channel (VIRTUAL CH NO.) 12 ch, and sub channels (SUB CH) 1, 2 and 3, and no broadcasting signal exists on the physical channel 12 ch. It is also assumed that these are not registered in the channel map. The second column (DIGITAL/ANALOG) in <figref idref="DRAWINGS">FIG. 4</figref> shows the kind or status of the physical channel in the channel map.

0030When the user selects “<b>12</b>-<b>2</b>” (digital channel number), the number is displayed on the television display as shown in <figref idref="DRAWINGS">FIG. 5</figref>, while no broadcasting signal exists on the physical channel 12 ch. Moreover, since the digital broadcasting signal with the virtual channel number of “12” is not registered in the channel map, “No Signal” is displayed on the display. When the user operates the Enter key (scan instruction) of the input unit <b>11</b> as an additional input, the entire range scanning for frequency band of the broadcasting signal is executed to search the digital broadcasting signal whose virtual channel number is “12”. As the digital broadcast 10 ch, whose virtual channel number is “12”, is detected as a result of the entire range scanning, it is received as shown in <figref idref="DRAWINGS">FIG. 6</figref>. Since it is not registered in the channel map at that time, the user performs the registration operation as needed.

0031Moreover, the user can perform by using the control unit <b>8</b> overall scanning to get a list of all digital channel numbers currently available. That is, upon receiving an instruction from the user through the input unit <b>11</b>, the control unit <b>8</b> scans the entire range of frequency band of the broadcasting signal by its scanning function to prepare a list of digital channels of which the signals exist, notifies its results, and registers it in the channel map. This operation is useful for the user to look over available channels.

0032The present invention can be modified in various ways without being limited to the abovementioned embodiment. For example, the STB <b>1</b> can be configured in such a way that it can receive NTSC analog broadcasting signals in addition to ATSC digital broadcasting signals. In this case, the tuner <b>2</b> is also capable of receiving broadcasting signals in the band where analog broadcasts are distributed, and the STB <b>1</b> is separately equipped with an analog decoder for decoding the analog broadcasting signals received by the tuner <b>2</b>.